Bullock and Fildes,1 in their monograph on hemophilia, gave a critical review of all reports in the literature dealing with the transmission of this disease. They supported the law promulgated by Nasse2 in 1820 that hemophilia was transmitted only through the female members of affected families but appeared only in the males. The reports of its apparent transmission through the male they discarded on the ground that it may have been introduced by unaffected females from unknown but affected families marrying into the family under observation. This point is not susceptible of proof one way or another, but on the basis of the work of Nasse and of Bullock and Fildes, practically all textbooks dealing with hemophilia now define it as an abnormal tendency to bleed, appearing only in the male sex, usually early in life, but transmitted only by the unaffected females.
In this connection I present